05 Fakultät Informatik, Elektrotechnik und Informationstechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6
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Item Open Access Abstract syntax of WS-BPEL 2.0(2008) Kopp, Oliver; Mietzner, Ralph; Leymann, FrankWS-BPEL 2.0 is the current version of the "Business Process Execution Language for Web Services". Until now, no formal definition of its syntax exists. We present a complete syntax of WS-BPEL 2.0 of both abstract and executable processes.Item Open Access Fragments of first-order logic over infinite words(2009) Diekert, Volker; Kufleitner, ManfredWe give topological and algebraic characterizations as well as language theoretic descriptions of the following subclasses of first-order logic for omega-languages: Sigma2, FO2, the intersection of FO2 and Sigma2, and Delta2 (and by duality Pi2 and the intersection of FO2 and Pi2). These descriptions extend the respective results for finite words. In particular, we relate the above fragments to language classes of certain (unambiguous) polynomials. An immediate consequence is the decidability of the membership problem of these classes, but this was shown before by Wilke and Bojanczyk and is therefore not our main focus. The paper is about the interplay of algebraic, topological, and language theoretic properties.Item Open Access Sub-lexical investigations: German particles, prefixes and prepositions(2013) Roßdeutscher, AntjeThe papers investigate constructions with P(repositional) elements in German. It aims at a comprehensive theory of the syntax-semantics interface for the different verbal constructions in German, including verb plus prepostional phrase, (separable) particle verbs, and (inseparable) prefix verbs. The constructions are given syntactic representations following minimalist principles as known from \textit{Distributive Morphology} (DM) according to which a single syntactic engine drives formation of both words and phrases. Among the syntactic principles the Split-P hypothesis plays a central role. A crucial feature of the approach is that the syntactic structures are used as input to the computation of semantic representations according to principles of Discourse Representation Theory (DRT). Several challenges that present themselves for a compositional theory of word- and phrase- formation with P-elements in German are accounted for in the paper: syntactic separability of verb-particle constructions vs non-separability of prefix-verbs; semantic restrictions in the P-elements to build constructions of the former and the latter type; syntactic alternations w.r.t. the realisation of figure and ground arguments and the semantic basis of these alternations. A particular challenge are the differences in the conceptual and aspectual contribution of the same prepositional root in different syntactic contexts.Item Open Access Coordination protocols for split BPEL loops and scopes(2007) Khalaf, Rania; Leymann, FrankThe document presents an approach to enable loops and fault handling, compensating scopes to be split among a set of BPEL processes running on different BPEL engines. A mechanism to split a scope or loop into multiple fragments is presented, then a protocol is defined that can be used to coordinate fragments of a loop or a scope so that those fragments run as if they had been in a single process. The requirements for running split scopes and loops are explained. For compensation, this paper focuses on explicit compensation and makes the assumption that compensation handing does not fail. Two protocols are defined such that they may be plugged into the WS-Coordination framework. The messages between the participant fragments and the coordinator are defined. The information about the participating processes that the coordinator needs to have is specified. An algorithm is provided to locate a fault handler in the hierarchy of scopes that can handle a particular BPEL fault. Additionally, the behavior of both participants and the coordinator are specified.Item Open Access Disambiguation and reambiguation(2009) Hamm, Fritz; Kamp, Hans; Solstad, Torgrim; Roßdeutscher, Antje (ed.)The papers in this volume developed as part of the two projects "The Role of Lexical Information in the Context of Word-formation, Sentence and Discourse" and the project "Representation of Ambiguities and their Resolution in Context". In the former, a theory of "-ung"-nominalisation in German has been developed. The two papers presented in this volume focus on the second part of the joint enterprise of the two projects, namely on disambiguation of "-ung"-nouns in context. Hamm and Kamp study a proto-typical example, "die Absperrung der Botschaft" "the cordoning-off of the embassy", which is three-way ambiguous. This DP can denote a material object (the fence used for cordoning-off), an event (the process of cordoning-off) or a result state (the embassy being cordoned off). Formally, this three-way ambiguity is represented by an underspecified DRS. The paper contributes a partial answer to the general question which contextual factors are responsible for the (partial) disambiguation of this DP in discourse. The disambiguation process is described on the level of DRT. Building on the results in the first paper, the second paper by Hamm and Solstad focuses on problems that arise in anaphora resolution of pronouns with ambiguous nouns like "die Absperrung der Botschaft" as antecedent. What happens if the selection restriction of the verb in the antecedent sentence and that of the consequent sentence are incompatible? This situation is exemplified in (1): (1) Die Absperrung der Botschaft wurde vorgestern von Demonstranten behindert. Wegen anhaltender Unruhen wird SIE auch heute aufrecht erhalten. "The cordoning-off of the embassy was hampered by protesters the day before yesterday. Due to continuing unrest, it [the state of being cordoned off] is sustained today as well." "Behindern" "to hamper" filters out both the entity-reading and the result state reading of "Absperrung", but the verb "aufrecht erhalten" "to sustain" requires the result state as its argument. Thus, in order for the anaphoric pronoun 'sie' to be resolved successfully, the first sentence should provide a result state which, however, is not available, if the result state reading has been erased. Hamm and Solstad show that the required result state can be reconstructed - even under the assumption that "behindern" erases the result state reading of the first sentence in (1). This is achieved in a process of "reambiguation". Reambiguation involves a non-monotonic inference process. The question arise what triggers this process and what its restrictions are. Hamm and Solstad provide formally precise answers to these questions. Again a combination of UDRT and the event calculus provide the framework where these puzzles can be solved.Item Open Access Propagation of states from BPEL process instances to Chevron models(2011) Schumm, David; Karastoyanova, Dimka; Leymann, Frank; Lie, SumadiThis report describes key aspects of a code library that we developed for the purpose of state propagation for business process monitoring on different levels of abstraction. The library supports the propagation of execution states of process instances based on the Business Process Execution Language (BPEL) to process models specified in the "Chevron" language. The Chevron language is an abstract, non-executable process language that we especially designed for abstract process instance monitoring purposes. The look and feel of this graphical language is similar to value chains. The basic concept of the Chevron language is based on Chevron-shaped charts which can be modeled in Microsoft PowerPoint to describe a process on a high level of abstraction. We aim at enabling the use of high-level process in order to monitor the instance status of a much more detailed, lower-level model. We describe the overall procedure of performing state projections along a concrete scenario. We describe a format for state propagation rules which define how the status of activities of a BPEL process instance should be projected to the elements of a Chevron model. We present a format to serialize process models in the Chevron language. We present a graphical template based on Scalable Vector Graphics (SVG) which we employ to render a stateful Chevron model graphically. The Chevron language is just one language to be used for abstract representation of process instances. However, the approach for state propagation is generic and can be applied for other languages, too.Item Open Access First-order fragments with successor over infinite words(2010) Kallas, Jakub; Kufleitner, Manfred; Lauser, AlexanderWe consider fragments of first-order logic and as models we allow finite andinfinite words simultaneously. The only binary relations apart from equalityare order comparison < and the successor predicate +1. We givecharacterizations of the fragments Sigma2 = Sigma2[<,+1] and FO2 = FO2[<,+1] interms of algebraic and topological properties. To this end we introduce thefactor topology over infinite words. It turns out that a language L is in theintersection of FO2 and Sigma2 if and only if L is the interior of an FO2language. Symmetrically, a language is in the intersection of FO2 and Pi2 ifand only if it is the topological closure of an FO2 language. The fragmentDelta2, which by definition is the intersection Sigma2 and Pi2 contains exactlythe clopen languages in FO2. In particular, over infinite words Delta2 is astrict subclass of FO2. Our characterizations yield decidability of themembership problem for all these fragments over finite and infinite words; andas a corollary we also obtain decidability for infinite words. Moreover, wegive a new decidable algebraic characterization of dot-depth 3/2 over finitewords. Decidability of dot-depth 3/2 over finite words was first shown by Glaßer andSchmitz in STACS 2000, and decidability of the membership problem for FO2 overinfinite words was shown 1998 by Wilke in his habilitation thesis whereasdecidability of Sigma2 over infinite words was not known before.Item Open Access WS-BPEL extension for semantic web services (BPEL4SWS), version 1.0(2008) Karastoyanova, Dimka; Van Lessen, Tammo; Leymann, Frank; Nitzsche, Joerg; Wutke, DanielThe Web Services Business Process Execution Language, version 2.0 (WS-BPEL 2.0 or BPEL for brevity) introduces a model for business processes based on Web services. A BPEL process orchestrates interactions among different Web services. The language encompasses features needed to describe complex control flows, including error handling and compensation behavior. BPEL for Semantic Web Services (BPEL4SWS) uses Semantic Web Service Frameworks to define a communication channel between two partner services instead of using the partner link which is based on WSDL 1.1. It enables describing activity implementations in a much more flexible manner based on ontological descriptions of service requesters and providers.Item Open Access Rankers over infinite words(2010) Dartois, Luc; Kufleitner, Manfred; Lauser, AlexanderWe consider the fragments FO2, the intersection of Sigma2 and FO2, the intersection of Pi2 and FO2, and Delta2 of first-order logic FO[<] over finite and infinite words. For all four fragments, we give characterizations in terms of rankers. In particular, we generalize the notion of a ranker to infinite words in two possible ways. Both extensions are natural in the sense that over finite words, they coincide with classical rankers and over infinite words, they both have the full expressive power of FO2. Moreover, the first extension of rankers admits a characterization of the intersection of Sigma2 and FO2 while the other leads to a characterization of the intersection of Pi2 and FO2. Both versions of rankers yield characterizations of the fragment Delta2. As a byproduct, we also obtain characterizations based on unambiguous temporal logic and unambiguous interval temporal logic.Item Open Access Methods for coreference visualization and annotation(2010) Burkovski, Andre; Heidemann, Gunther; Kobdani, Hamidreza; Schütze, HinrichIn this report we present methods for visualization of coreferences. We use Self Organizing Maps, graph-based models, and text-based techniques to visualize coreference information from a pair-wise model and offer an interactive presentation of the feature space. We introduce our software system and several visualizations of the Self Organizing Map. The visualizations enable the user to explore the feature space, provide insights for feature engineering and allow a fast annotation of data with coreference information.
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